Linear crosstalk in wavelength-division-multiplexed optical-fiber transmission systems

Design rules are given for overcoming the effects of optical crosstalk between digital PCM channels, when introducing wavelength-division-multiplexed (WDM) operation into optical-fiber systems. Power penalties are derived for two-, three-, and four-channel symmetric systems in the presence of interchannel interference, using a simple model for the recovery of the eye opening at a digital regenerator. The model is also extended to give a generalized, deterministic solution for the power penalties in asymmetric multichannel WDM systems, and the limitations of the model are discussed.